1. Field of the Invention
The present invention relates to communications systems. More particularly, the present invention relates to systems and methods for exchanging data and audio between cellular telephones and landline telephones.
2. Background Information
Many users (e.g., consumers, business persons, etc.) possess both a landline telephone and a cellular telephone. While telephone infrastructure varies from country to country, the United States infrastructure provides a useful starting point for purposes of this description. In the United States, a landline telephone can be a cordless or corded telephone that is coupled to a central office (“CO”) of a local exchange carrier (“LEC”) such as a Regional Bell Operating Company (“RBOC”), a competitive local exchange carrier (“CLEC”), and so on. Cordless telephones have no cord between the handset and base. Instead, the handset and base each have a radio transmitter, receiver and antenna to allow communication between the handset and base. Typically, the handset includes a rechargeable battery, and the base is powered by current from an alternating current (“AC”) outlet (e.g., of a house, office, etc.). In a residential environment, the base is typically coupled to the CO via one or more wires, such as an RJ-11 wire that couples the base to an RJ-11 jack on a wall. The RJ-11 jack is typically coupled to the CO via a twisted-pair wire.
As used to describe the background and embodiments of the present invention, the term “coupled” encompasses a direct connection, an indirect connection, or a combination thereof. Two devices that are coupled can engage in direct communication, in indirect communication, or a combination thereof. Moreover, two devices that are coupled need not be in continuous communication, but can be in communication typically, periodically, intermittently, sporadically, occasionally, and so on. Further, the term “communication” is not limited to direct communication, but also includes indirect communication.
The range of effective communications between the handset and base can be from about 10 feet to several miles depending on factors such as product design, operating radio frequency, environmental conditions, and legal restrictions (e.g., laws, regulations, etc.). Examples of known operating radio frequencies for cordless telephone communications in the United States include 900 Megahertz (“MHz”), 2.4 Gigahertz (“GHz”), 5.8 GHz, a combination thereof, and so on.
An example of a cellular telephone is a handheld cellular radio transceiver (transmitter/receiver) that operates in a cellular service area composed of a plurality of cells. Each cell is populated with one or more low-powered radio transceivers that communicate with the cellular telephones in or about the cell. Adjoining cells typically operate at different radio frequencies. Each cell's radio transceiver is coupled to a Mobile Telephone Switching Office (“MTSO”), that can monitor the movement, if any, of the cellular telephone (e.g., by determining or receiving signal strength indicators corresponding to the cellular telephone) through the cell such that at the proper time the cellular telephone can be handed-off from a current cell to a next cell. Examples of cellular telephone systems include Personal Communications Service (“PCS”) systems, Global System for Mobile Communications (“GSM”) systems, Code Division Multiple Access (“CDMA”) systems, Time Division Multiple Access (“TDMA”) systems, analog and/or digital Advanced Mobile Phone Service (“AMPS”) systems, and so on. Cellular telephone systems in the United States operate at or around 1900 MHz (e.g., GSM 1900 systems, Digital AMPS, and CDMA 1900 systems), in the 800-900 MHz range (e.g., analog AMPS), and so on.
Many users own both a landline telephone and a cellular telephone. There is a strong user desire to use cellular telephone services (e.g., to take advantage of free night and weekend calls) from the comfort of the home landline telephone. Other users want to use the handset of their cordless telephone to communicate with others via the wireless network of the cellular telephone. For example, a user may want to take an incoming call received by the cellular telephone using the cordless handset while the cellular telephone is charging in its docking station. As another example, the user may want to access or transfer data between the cellular telephone and his home telephone (e.g., access or copy the cellular address book into his home telephone).
Known systems that couple a cellular telephone to a landline telephone rely on a physical connection to exchange control information, data and audio. Problems with such systems include, for example, mechanical contour, physical connector, electrical, and protocol problems. With respect to mechanical contour, a cellular telephone cradle is required and this cradle must physically fit the cellular telephone. A physical connector matching the cellular telephone connector is required, and the exact electrical characteristics of each cellular telephone must be followed. With respect to protocol, the exact protocol and command set provided by the cellular telephone must be used. None of the above factors are standardized, and existing cellular telephones differ radically in the above attributes. Hardware (e.g., mechanical, electrical, and electronic) and software development is typically required to support new cellular telephones. In view of the foregoing, it can be appreciated that a substantial need exists for systems and methods that can advantageously provide for wireless communications between cellular telephones and landline telephones.